key: cord-0924990-50l4yzfo
authors: He, Lu; Zeng, Cheng; Xu, Wanzhou; Li, Ying; Lin, Ren; Xie, Xiaojie; Xia, Hongmiao; Tang, Shiqi; Xu, Lijuan; Chen, Changzheng
title: Dynamic changes of serum SARS-CoV-2 antibody levels in COVID-19 patients
date: 2022-04-21
journal: J Infect
DOI: 10.1016/j.jinf.2022.04.032
sha: 4de82235c02592f3790bb1257523c881722cdd6d
doc_id: 924990
cord_uid: 50l4yzfo

nan

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in December 2019 and spread rapidly and globally, leading to a worldwide pandemic currently. As of April 4, 2022, more than 489 million confirmed COVID-19 cases and 6 million deaths were reported to WHO around the world [1] . Evaluating the durability of the humoral immune response to SARS-CoV-2 is essential to understand the susceptibility of COVID-19 patients to the same virus after recovered from the infection. Recently, it has been reported in neutralization assays using SARS-CoV-2 virus that neutralization antibodies titer is correlated with protection against reinfection [2] . Serum immunoglobulin M (IgM) and immunoglobulin G (IgG) against SARS-CoV-2 were detectable within the first several weeks after symptom onset [3] . To date, there are few data on long-term of antibodies response to SARS-CoV-2 after initial infection. Here, the aim of this study is to investigate the duration or stability of viral-specific humoral responses in COVID-19 recovered patients. Continuous variables were present as median and interquartile range (IQR) and the Kruskall-Wallis test was applied. A p-value less than 0.05 was statistically significant. All statistical analyses and scientific graphics were made by using SPSS 20.0.

From 17 January 2020 to 7 March 2020, a total of 61 COVID-19 patients were recruited in our study. The median age was 34 years (IQR, 30-47). 72.13% (44/61) were women and 27.87% (17/61) men. 29, 53, 30 and 61 specimens were collected 1-30 days, 31-60 days, 61-120 days, and 296-368 days after the onset of symptoms, respectively. We illustrate the overall profile of serum IgM, IgG, and neutralization antibodies against SARS-CoV-2 from day 1 to 368 after illness onset in Table 1 (Fig 1) . The positive rates of IgM were 65.52%, 58.49%, 80.00% and 22.95%, respectively (Fig 2) (Fig 1) . The positive rates of IgG were 96.55%, 100.00%, 100.00% and 81.97%, respectively (Fig 2) . The median serum neutralization antibodies level was 35.32 (IQR, 12.16, 160.60) AU/mL in 1-31 days, increased to 54.43 (IQR, 23.98, 145.74) AU/mL in 31-60 days and 80.13 (IQR, 56.98, 202.36) AU/mL in 61-120 days, but the difference was not statistically significant. The neutralization antibodies level in days 296 to 368 markedly reduced to 14.30 (IQR, 7.77, 27.9) AU/mL, which decreased significantly compared with other time periods (Fig 1) . The positive rates of neutralization antibodies were 79.31%, 92.45%, 100.00% and 67.21%, respectively (Fig   2) . Some studies performed at the beginning of the COVID-19 pandemic showed that the amount of anti-SARS-COV-2 IgM/IgG antibodies decreased in several months post onset of symptoms [4, 5] . However, Gong X et al. found that anti-SARS-CoV-2 IgG can last for at least 9 months in patients with a history of natural infection [6] . Kaygusuz S et al. also showed that both IgG and neutralization antibodies levels continued unabated after 9 months of follow-up [7] . Yousefi Z et al. found that the level of anti-SARS-CoV-2 IgG antibody was detectable at their highest level for 3 months, and a certain amount of anti-SARS-COV-2 IgG antibody could be detected in the serum of recovered patients up to 15 months [8] . The humoral immunity persisted for up to 18 months in patients with mild COVID-19 [9] . The maximum duration of neutralizing antibodies and IgG antibodies could be long-lasting based on Linear Mixed Models, especially IgG [10] . 

Neutralizing antibody levels are highly predictive of immune protection from symptomatic SARS-CoV-2 infection

Molecular and serological investigation of 2019-nCoV infected patients: implication of multiple shedding routes

Seroprevalence of anti-SARS-CoV-2 antibodies in COVID-19 patients and healthy volunteers up to 6 months post disease onset

Decline of SARS-CoV-2-specific IgG, IgM and IgA in convalescent COVID-19 patients within 100 days after hospital discharge

Long-term immune responses in patients with confirmed novel coronavirus disease-2019: a 9-month prospective cohort study in Shanghai

INVESTIGATION AND LONG-TERM MONITORING OF THE PRESENCE OF NEUTRALIZING ANTIBODY IN PATIENTS WITH COVID-19 DISEASE OF DIFFERENT CLINICAL SEVERITY

Long-Term Persistence of Anti-SARS-COV-2 IgG Antibodies

Persistent Antibody Responses up to 18 Months after Mild SARS-CoV-2 Infection

Generation and persistence of S1 IgG and neutralizing antibodies in post-COVID-19 patients